Adolescents in the United States continue to have the highest rates of teen pregnancy and one of the highest rates of sexually transmitted diseases in the post-industrial world. The mass media have been have been blamed for increasingly STD's. However, little is known about how media depictions affect tense's sexual beliefs and behaviors. This five-year project is one of the first population-based investigations of the link between teens' exposure to sexual content in the media and their sexual beliefs and behaviors. The project is based on the Media Practice Model that assumes that adolescents must choose among the array of media now available to them. Consequently, all teens will not have the same "diet" of sexual media content, and all will not be affected in the same ways. Data will be gathered in five phases: First, all 7th and 8th grade students (about 3,000) enrolled in nine middle schools in central North Carolina will complete a self-administered questionnaire about their use of the mass media. Second, the content the teens most frequently in that medium to create a measure of their sexual media diet -- the time each teen spends attending to sexual content in the media. Third, a stratified (by race and gender) random sample of 1,000 of the students who completed the in-school media questionnaire about their use of the mass media. Second, the content the teens most frequently attend to in seven different media including television, movies, magazines, books, the internet, etc. will be collected and analyzed for risky and health sexual portrayals. This is the first time the sexual content of the media has been assessed across the array of media teens attend to. The time each teen spends with each medium than will then be weighted by medium to create a measure of their sexual media diet -- the time each teen spends attending to sexual content in the media. Third, a stratified (by race and gender) random sample of 1,000 of the students who completed the in school media questionnaire will be interviewed in their homes about their sexual knowledge, beliefs, and behaviors using a computer-assisted interviewing system to ensure privacy and confidentiality. Two years later, in Phases 4 and 5 of the project, the 1,000 students will be reinterviewed in their homes and another sample of media content will be analyzed to assess how media diets and sexual attitudes and behaviors have changed. The longitudinal and comprehensive design of this study will provide the most current understanding of how the mass media affect the sexual beliefs and behaviors of adolescents.